<html>
<head>
  <link type="text/css" rel="stylesheet" href="javascript:var s='';var ci=Components.interfaces;for(var p in ci){s += ci[p]+'|';};'.foo {background-color: red; font-family:&quot;'+escape(s)+'&quot;};'">
<script>
function doit() {
 var d = document.getElementById("foo");
 var style = window.getComputedStyle(d, null);
 document.write(unescape(style.getPropertyCSSValue("font-family").cssText).replace(/\|/g, "<br>"));
}
</script>
</head>
<body onload="doit()">
0
<div id="foo" class="foo">
bar
</div>
1
</body>
</html>
